[0001] This invention relates to the catalytic decomposition of tertiary butyl hydroperoxide
(TBHP). More particularly, this invention relates to a method for the preparation
of tertiary butyl alcohol (TBA) by the catalytic decomposition of tertiary butyl hydroperoxide.
Still more particularly, this invention relates to a method wherein an alumina supported
lead oxide catalyst is used to catalyze the substantially selective decomposition
of tertiary butyl hydroperoxide to tertiary butyl alcohol.
[0002] It is known to react isobutane with oxygen, either thermally or catalytically, to
form a peroxidation reaction product wherein the principal peroxide that is formed
is tertiary butyl hydroperoxide. It is also known to thermally or catalytically decompose
the tertiary butyl hydroperoxide to form tertiary butyl alcohol.
[0003] Sanderson et al. disclose the use of a variety of catalysts for the decomposition
of tertiary butyl hydroperoxide in a series of U. S. patents, including a catalyst
composed of unsupported nickel, copper, chromia and iron (U. S. Patent No. 4,704,482),
a catalyst composed of iron, copper, chromia and cobalt (U. S. Patent No. 4,705,903),
a catalyst composed of a base treated hydrogenation catalyst from groups VIA or VIII
of the Periodic Table (U. S. Patent No. 4,742,179), a catalyst consisting essentially
of nickel, copper, chromium and barium (U. S. Patent No. 4,873,380), a catalyst composed
of a metal phthalocyanine promoted with a rhenium compound (U. S. Patent No. 4,910,349),
a catalyst composed of a base promoted metal phthalocyanine compound (U. S. Patent
No. 4,912,269), a catalyst composed of a soluble ruthenium compound promoted with
a bidentate ligand (U. S. Patent No. 4,912,033), a catalyst composed of a metal porphine
such as iron (III) or manganese (III) promoted with an alkyl thiol or an amine, a
catalyst composed of an imidazole promoted metal phthalocyanine compound (U. S. Patent
No. 4,912,266), (U. S. Patent No. 4,922,034), a catalyst composed of a metal phthalocyanine
promoted with a thiol and a free radical inhibitor (U. S. Patent No. 4,922,035), a
catalyst composed of a borate promoted metal phthalocyanine (U. S. Patent No. 4,922,036),
or a catalyst composed of a soluble ruthenium compound and an iron compound such as
an acetate, a borate, a bromide, a chloride, a 1,3-propanedionate, a 2-ethyl-hexanoate,
an iodide, a nitrate, a 2,4-pentanedionate, a perchlorate or a sulfate (U. S. Patent
No. 5,025,113).
[0004] As stated, when isobutane is reacted with molecular oxygen, the principal products
of the reaction are tertiary butyl alcohol and tertiary butyl hydroperoxide. However,
minor amounts of other contaminants are also formed. A minor amount of water will
be formed, which will normally amount to 0.5 to 1 wt.% of the reactor effluent. The
amount of byproduct water that is produced is a function of the severity of the reaction
conditions employed and will tend to increase as the severity of the reaction conditions
is increased.
[0005] As indicated, tertiary butyl hydroperoxide is useful as a raw material for the manufacture
of tertiary butyl alcohol. The tertiary butyl alcohol can be formed by catalytic decomposition
of the tertiary butyl hydroperoxide. US-A-3,472,876 discloses a process wherein an
oxygen-containing gas was charged to a reactor containing isobutane and an oxidation
catalyst to provide a reaction mixture comprising tertiary butyl alcohol, tertiary
butyl hydroperoxide, acetone, and tertiary butyl ether. The reported results in the
patent indicate that there was a comparatively low rate of conversion and a comparatively
poor selectivity of the reaction to tertiary butyl alcohol.
[0006] There is a need for a catalytic decomposition of tertiary butyl hydroperoxide to
tertiary alcohol at a higher conversion rate and an improved selectivity over the
prior art.
[0007] In accordance with the present invention, a solvent solution of a tertiary butyl
hydroperoxide charge stock is brought into contact with a catalytically effective
amount of a hydroperoxide decomposition catalyst in a hydroperoxide decomposition
reaction zone in liquid phase, preferably with agitation, to convert the tertiary
butyl hydroperoxide to decomposition products, principally tertiary butyl alcohol,
the hydroperoxide decomposition catalyst consisting essentially of alumina having
from 0.5 to 25 wt.% of lead oxide deposited thereon. Tertiary butyl alcohol is recovered
from the products of the hydroperoxide decomposition reaction.
[0008] The tertiary butyl alcohol will not be the only decomposition product that is formed.
Minor amounts of other oxygen-containing materials such as those listed above will
also be formed.
[0009] The starting materials for the process of the present invention are a tertiary butyl
hydroperoxide feedstock and an alumina supported lead oxide catalyst.
The Tertiary Butyl Hydroperoxide Feedstock
[0010] The tertiary butyl hydroperoxide charge stock may comprise an isobutane oxidation
product wherein the tertiary butyl hyroperoxide is dissolved in a mixture of isobutane
and tertiary butyl alcohol or may comprise an isobutane oxidation product enriched
by the addition of tertiary butyl alcohol, such that the solution of tertiary butyl
alcohol in the mixture of isobutane with tertiary butyl alcohol contains from 5 to
30 wt.% of tertiary butyl hydroperoxide.
[0011] Alternatively, the isobutane reaction product may be charged to a distillation zone
where unreacted isobutane is removed as a distillate fraction for recycle to thereby
provide a solution of tertiary butyl hydroperoxide in tertiary butyl alcohol containing
5 to 30 wt.% of tertiary butyl hydroperoxide.
The Catalyst System
[0012] The hydroperoxide decomposition catalyst to be used in accordance with the present
invention consists essentially of alumina having from about 0.5 to about 25 wt.% of
lead oxide deposited thereon.
Catalytic Decomposition of Tertiary Butyl Hydroperoxide
[0013] The process of the present invention may be conducted batchwise in kettles or by
continuously passing the reactants through a tubular reactor.
[0014] The catalytic decomposition of the tertiary butyl hydroperoxide is preferably conducted
at a temperature within the range of 20° to 250°C, preferably 60° to 120°C, and more
preferably, at a temperature within the range of 80° to 100°C. The reaction is preferably
conducted at a pressure sufficient to keep the reactants and the reaction products
in liquid phase. A pressure of 0.1 to 69 MPa (0 to 10,000 psig), preferably 0.1 to
7.0 MPa (0 to 1000 psig) may be used, if desired.
[0015] Flow rates of the charge solution to the reaction zone should be adjusted in order
to provide an appropriate contact time within the reactor. In a batch process, the
holding time may suitably be from 0.5 to 10 hours, and more preferably 1 to 3 hours.
[0016] In accordance with a preferred embodiment of the present invention, isobutane is
reacted with oxygen in an oxidation zone under oxidation reaction conditions including
a temperature of 135 to 155°C., a pressure of 2.1 to 5.6 MPa (300 to 800 psig), and
a holding time of 2 to 6 hours to provide an initial oxidation reaction product comprising
unreacted isobutane, tertiary butyl hydroperoxide, tertiary butyl alcohol, and oxygen-containing
by-products. The initial oxidation reaction product is then used as the tertiary butyl
hydroperoxide charge stock of the present invention. If the concentration of tertiary
butyl hydroperoxide in the tertiary butyl hydroperoxide charge stock is more than
30 wt.% of the initial oxidation reaction product, the initial oxidation reaction
product can be diluted with an amount of tertiary butyl alcohol sufficient to lower
the concentration of the tertiary butyl hydroperoxide to a desired percentage, to
provide, for example, a tertiary butyl hydroperoxide charge stock containing from
15 to 25 wt.% of tertiary butyl hydroperoxide.
[0017] Alternatively, the initial oxidation reaction product may be fractionated in any
appropriate manner (e.g., by distillation in a distillation zone) to remove the isobutane
therefrom for recycle and to provide a solution of tertiary butyl hydroperoxide and
tertiary butyl alcohol which will normally contain from 5 to 30 wt.% of tertiary butyl
hydroperoxide.
[0018] The solution of tertiary butyl hydroperoxide in tertiary butyl alcohol is then charged
to a catalytic hydroperoxide decomposition zone where it is brought into contact with
an alumina supported lead oxide catalyst to substantially selectively convert the
tertiary butyl hydroperoxide to tertiary butyl alcohol with high yields and selectivities.
[0019] When the process of the present invention is practiced in a continuous manner by
continuously charging the tertiary butyl hydroperoxide charge stock to a reactor containing
a fixed bed of pelleted hydroperoxide decomposition catalyst, the space velocity is
suitably in the range of 0.5 to 3 volumes of tertiary butyl hydroperoxide charge stock
per volume of catalyst per hour. Preferably, the space velocity is within the range
of 1 to 2 volumes of tertiary butyl hydroperoxide charge stock per volume of catalyst
per hour.
[0020] The reaction product from the tertiary butyl hydroperoxide decomposition step may
then be fractionated in any suitable manner, such as by distillation to recover the
tertiary butyl alcohol.
EXAMPLES
[0021] The invention will be further illustrated by the following non-limiting examples.
Procedure
[0022] The reactor that was used for the experiments was a stainless steel tube (12.3 x
360mm) which was electrically heated. Liquid feed was pumped into the bottom of the
reactor using a Ruska® dual drive pump. Pressure was regulated using a Skinner Uni-Flow®
valve and a Foxboro® controller. Samples were collected at the top of the reactor,
cooled to ambient temperature, filtered and analyzed by Gas Chromatography. The analysis
of the feed and of the products obtained is reported in the following tables.
Example 1
[0023] In this example, the catalyst consisted essentially of lead oxide supported on alumina.
TABLE 1
CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL |
RUN |
A |
1 |
2 |
3 |
4 |
Catalyst |
|
PbO on Al₂O₃ |
PbO on Al₂O₃ |
PbO on Al₂O₃ |
PbO on Al₂O₃ |
Catalyst (cc) |
|
100 |
100 |
100 |
100 |
Pressure (MPa) |
|
3.5 |
3.5 |
3.5 |
3.5 |
Feed Rate (cc/Hr.) |
|
50 |
50 |
50 |
50 |
Temperature (°C) |
|
80 |
100 |
120 |
140 |
Time on Stream (Hr) |
|
4 |
4 |
4 |
4 |
Space Vel. (cc/cc) |
|
0.5 |
0.5 |
0.5 |
0.5 |
TBHP Conversion (mol.%) |
|
72.5 |
82.1 |
95.0 |
98.3 |
Selectivity IC4= (mol.%) |
|
-0.0 |
0.0 |
-0.0 |
0.0 |
Sel. Acetone (mol.%) |
|
8.5 |
14.0 |
18.7 |
27.9 |
Sel. Methanol (mol.%) |
|
1.4 |
2.6 |
5.0 |
8.0 |
Sel. TBA (mol.%) |
|
83.9 |
80.3 |
78.1 |
70.9 |
Sel. DTBP (mol.%) |
|
7.7 |
5.7 |
3.2 |
1.3 |
Remarks |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
Composition, wt% |
|
|
|
|
|
IC4= |
0.001 |
0.000 |
0.001 |
0.000 |
0.002 |
MEOH/MF |
0.016 |
0.083 |
0.162 |
0.337 |
0.552 |
Acetone |
0.008 |
0.765 |
1.429 |
2.206 |
3.385 |
TBA |
79.968 |
92.463 |
93.740 |
95.496 |
95.005 |
DTBP |
0.055 |
0.917 |
0.785 |
0.521 |
0.251 |
TBHP |
19.146 |
5.270 |
3.419 |
0.948 |
0.333 |
TABLE 2
CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL |
RUN |
A |
5 |
6 |
7 |
8 |
Catalyst |
|
PbO on Al₂O₃ |
PbO on Al₂O₃ |
PbO on Al₂O₃ |
PbO on Al₂O₃ |
Catalyst (cc) |
|
100 |
100 |
100 |
100 |
Pressure (MPa) |
|
3.5 |
3.5 |
3.5 |
3.5 |
Feed Rate (cc/Hr.) |
|
100 |
100 |
100 |
100 |
Temperature (°C) |
|
80 |
100 |
120 |
140 |
Time on Stream (Hr) |
|
4 |
4 |
4 |
4 |
Space Vel. (cc/cc) |
|
1.0 |
1.0 |
1.0 |
1.0 |
TBHP Conversion (mol.%) |
|
15.3 |
40.8 |
83.4 |
97.3 |
Selectivity IC4= (mol.%) |
|
-0.1 |
-0.0 |
-0.0 |
0.0 |
Sel. Acetone (mol.%) |
|
11.1 |
12.0 |
18.1 |
35.5 |
Sel. Methanol (mol.%) |
|
1.9 |
2.6 |
5.8 |
10.5 |
Sel. TBA (mol.%) |
|
80.9 |
82.0 |
79.2 |
64.0 |
Sel. DTBP (mol.%) |
|
8.0 |
6.0 |
2.7 |
0.5 |
Remarks |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
Composition, wt% |
|
|
|
|
|
IC4= |
0.001 |
0.000 |
0.000 |
0.000 |
0.004 |
MEOH/MF |
0.016 |
0.036 |
0.088 |
0.343 |
0.713 |
Acetone |
0.008 |
0.216 |
0.612 |
1.872 |
4.275 |
TBA |
79.968 |
82.443 |
86.692 |
93.593 |
93.536 |
DTBP |
0.055 |
0.245 |
0.438 |
0.401 |
0.127 |
TBHP |
19.146 |
16.226 |
11.335 |
3.176 |
0.518 |
TABLE 3
CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL |
RUN |
A |
9 |
10 |
11 |
Catalyst |
|
PbO on Al₂O₃ |
PbO on Al₂O₃ |
PbO on Al₂O₃ |
Catalyst (cc) |
|
100 |
100 |
100 |
Pressure (MPa) |
|
3.5 |
3.5 |
3.5 |
Feed Rate (cc/Hr.) |
|
200 |
200 |
200 |
Temperature (°C) |
|
100 |
120 |
140 |
Time on Stream (Hr) |
|
4 |
4 |
4 |
Space Vel. (cc/cc) |
|
2.0 |
2.0 |
2.0 |
TBHP Conversion (mol.%) |
|
30.5 |
77.3 |
92.3 |
Selectivity IC4= (mol.%) |
|
-0.0 |
0.0 |
-0.0 |
Sel. Acetone (mol.%) |
|
12.7 |
20.1 |
29.8 |
Sel. Methanol (mol.%) |
|
2.5 |
6.0 |
11.0 |
Sel. TBA (mol.%) |
|
82.5 |
77.2 |
69.3 |
Sel. DTBP (mol.%) |
|
4.8 |
2.7 |
0.9 |
Remarks |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
H₂O Free Basis |
Composition, wt% |
|
|
|
|
IC4= |
0.001 |
0.000 |
0.001 |
0.000 |
MEOH/MF |
0.016 |
0.068 |
0.333 |
0.708 |
Acetone |
0.008 |
0.488 |
1.926 |
3.398 |
TBA |
79.968 |
84.992 |
92.240 |
93.509 |
DTBP |
0.055 |
0.281 |
0.379 |
0.191 |
TBHP |
19.146 |
13.297 |
4.354 |
1.474 |
[0024] A 19.1% solution of TBHP in TBA was converted in good yield to TBA over a heterogenous
lead oxide on alumina catalyst. For example, at 80°C using a 100 cc reactor and a
space velocity of 0.5, a 72.5% conversion of TBHP was obtained with the following
selectivities: TBA 83.9%; DTBP 7.7%; acetone 8.5%; methanol 1.4%.
1. A method for the decomposition of tertiary butyl hydroperoxide to tertiary butyl alcohol,
wherein a solvent solution of tertiary butyl hydroperoxide charge stock is brought
into contact with a hydroperoxide decomposition catalyst, characterized in that said
hydroperoxide decomposition catalyst comprises lead oxide supported on alumina.
2. A method as claimed in Claim 1, wherein the solvent comprises tertiary butyl alcohol,
or a mixture thereof with isobutane.
3. A method as claimed in Claim 1 or Claim 2, wherein a solution of a tertiary butyl
hydroperoxide charge stock that contains from 5 to 30 wt.% of tertiary butyl hydroperoxide
is brought into contact with a catalytically effective amount of a hydroperoxide decomposition
catalyst in a hydroperoxide decomposition reaction zone in liquid phase under hydroperoxide
conversion conditions including a temperature within the range of 20° to 250°C. and
a pressure of 0.1 to 7 MPa (0 to 1,000 psig) to convert said tertiary butyl hydroperoxide
to decomposition products, principally tertiary butyl alcohol, characterized in that
said hydroperoxide decomposition catalyst consists essentially of alumina having deposited
thereon from 0.5 to 25 wt.% of lead oxide.
4. A method as claimed in anyone of Claims 1 to 3, wherein the temperature is in the
range of 40° to 150°C. and the pressure is 0.1 MPa.